1. Field of the Invention
The invention relates to a torque detecting device that includes a magnetic element, and an electric power steering system including the torque detecting device.
2. Description of Related Art
A conventional torque detecting device includes a magnetism collecting unit and a sensor unit. The magnetism collecting unit is integrated with a pair of magnetism collecting rings through resin molding. The magnetism collecting unit includes a fitted recessed portion and a flat plate-shaped fitting portion that surrounds the fitted recessed portion. The sensor unit includes a magnetic element. The sensor unit includes the magnetic element, a fitted protruding portion with a cylindrical shape that holds the magnetic element, a flat plate-shaped fitting portion that surrounds the fitted protruding portion, and a seal member that is fitted to the fitted protruding portion. The respective fitting portions of the magnetism collecting unit and the sensor unit are fastened to each other by using a plurality of fixing screws in a state where the fitted protruding portion is inserted into the fitted recessed portion. Thus, the relative positions of the element facing portion of the magnetism collecting ring and the magnetic element are determined. The seal member is disposed between the fitted recessed portion and the fitted protruding portion. The seal member seals a gap between the fitted recessed portion and the fitted protruding portion. Japanese Patent Application Publication No. 2008-249598 (JP 2008-249598 A) shows an example of the configuration of the conventional torque detecting device.
In the conventional torque detecting device, the seal member needs to be provided, for example, between the fitting portion of the sensor unit and the fitting portion of the magnetism collecting unit so that the waterproof performance for the magnetic element is ensured, or the fitting portions need to be fastened by using the plurality of fixing screws so that a gap between the fitting portions is decreased. Accordingly, the number of components may increase, which may increase weight and cost.